This is a 11x5.5E Electric ONLY Composite Propeller from Advanced Precision Composites. FEATURES: Gray composite one-piece construction Comes in a bag attached to a header card Gray composite one-piece construction INCLUDES: Five composite adapter rings One APC 11x5.5E Electric composite propeller REQUIRES: ALL props require balancing, this is VERY important, use TOPQ5700. May need prop reamer, use GPMQ5005 (SAE) or GPMQ5007 (Metric) SPECS: Diameter: 11" Pitch: 5.5 Hub inner diameter: 0.25" cdh8/26/03 ir/jxs